simpleFoam source code
 

Hi,

In simpleFoam source code, what do the following lines (in Ueqn.H) mean?

Ueqn().relax();
eqnResidual = solve
( Ueqn() == -fvc::grd(p)
).initial Residual()

I understand the part Ueqn()== -fvc::grad(p), please someone explain the rest. Thank you

Hello,

Ueqn().relax();
this is for under-relaxing the momentum equation.


Correct me if I am wrong, but I think, the two lines with "initialResidual" are for stopping the whole solution process once the residuals of all equations are low enough.

Regards, Markus.

Hi,

not exactly. The code

assigns the initial residual of the equation to be solved to the existing variable 'eqnResidual' and solves the equation within a single statement.

The check, whether the convergence criterion is satisfied is done later (see file convergenceCheck.H).

HTH, Jean-Peer.